Bomb and method of making same



April 28, 1942. H. v. THADEN 2,2 1,213

BOMB AND METHOD OF MAKIfiG SAME Filed Dec. 23, 1938 2 Sheets-Sheet 1 a ','F"||3-1.- f WW 1mm M' m wm mwm BOMB AND METHOD OF MAKING SAME Filed Dec. 23, 1938 2 Sheets-Sheet 2 FIE. 13.

M 17206761021" I J; #595587 V. 7/ /4DE/V,

Patented Apr. 28, 1942 UNITED STATES PATENT OFFICE This invention relates to improvements in a method of manufacturing shells, aerial bombs or the like and to the improved product resulting from the practice of the method.

One object of the invention is to provide an act of winding a blank such asshown in Figur 2,

- and illustrates a further step in the method:

Gil

improved bomb and method of making the same whereby the bomb will have a laminated body of suflicient strength to withstand the forces of impact with a hard surface target through which the bomb is required to penetrate before the usual delayed action fuse becomes operative.

Another object is to provide an improved method for making a bomb capable of penetrating an extremely hard surface without breaking up when dropped from an altitude sufficiently high to allow penetration of the maximum diameter of the bomb through a mass of concrete of'substantial thickness lying on a bed of crushed rock or the like.

Other objects are to provide a method of low cost of bomb manufacture and to improve ballistics and aerodynamics.

In some bombs heretofore made, the sudden deceleration involved in the bomb striking and penetrating a mass of concrete or similar hard substance causes the powder in the bomb to set up forces which act analogous to'a liquid of very high density and to consequently exert an enormous pressure which .acts radially on the shell. Such pressure varies approximately uniformly from zero at the tail of the bomb to a maximum at the head thereof.

In bombs of conventional types, failures frequently develop hoop-like tension cracks in the shell, tearing of .the longitudinal butt welds of the shell or plastic deformation of the shell producing an outward bump near the head of. the bomb in the unpenetrated portion thereof which is exterior to the plane of the hard surface of the target.

The present invention aims to produce a method and a resulting bomb which will overcome the suggested shortcomings of the prior conventional practice. For a full disclosure of the invention, reference should be made to the following detail description, the accompanying drawings and the appended claims.

Referring to the drawings:

Figure 1 is a plan view of a strip ofmetal stock which is provided as one of the initial steps in my improved method of producing a bomb;

Figure 2 is a view of a blank or a portion severed from the strip of Figure 1;

Figure 4 is a side elevation of the completed bomb made in accordance with the present invention', with parts shown in section in the in terest bf cleamess; and a Figure 5 is an elevation of the improved bomb of my invention made in accordance with the novel'method; and

Figure 6 illustrates a variationin the shape-of the blank which will be used to produce a bomb wherein the tapered of straight.

Figure 'l is a detail cross sectional view of a mandrel showing a clamp to grasp the end of a strip to be wound Figure 8 is a perspective view of a strip wound on the mandrel and illustrating a temporary clamp for holding the strip so as to prevent the same from uncoiling prior to its convolutio'ns being welded or otherwise secured:

Figure 9 is a detail view of the temporary clamp shown in Figure 8;

Figure 10 is a fragmentary detail view illustrating means of uniting the fins to the body of the bomb; 3

Figure 11 is a view partly in section and partly in elevation of a modified type of bomb:

Figure 12 is a view partly in section and partly in elevation showing a bomb constructed of two axially aligned coiled body portions:

Figure 13 is a view in l ngitudinal section'illustrating analtemative' bodiment of the invention;

Figure 14 is an elevation of a portion of a bomb illustrating the manner of welding or otherwise securing adjacent convolutions thereof to one another; v

Figure 15 is a perspective view of a portion of a bomb during the coiling thereof; and

Figure 16 is a detail view showing a tapered mandrel and a portion of a bomb in the act of being coiled thereon.

edge may be arcuate instead facture, an elongated strip of either ferrous or non-ferrous metal is provided. This is severed along the oppositely inclined diagonal lines a and Figure 3 is a view of a rotary mandrel in the b and also along the line 0 which is perpendicular to the parallel side edges of the strip. The

results of the cutting operations performed on thestrip along the lines such as a and 1: will produce a metal blank such as shown in Figure 2. In the manufacture of a large order of bombs of the same size, all of the blanks will be duplicates and it will be apparent from the manner of cutting described that there will be no waste of material. This blank when convoluted will provide, I a body portion shown in Figures 4 and 13. .If

the strip is cut on the lines o and b, this resultant blank when convoluted produces a body portion shown in-Figure l2.

' The next step in the method of manufacture is to tightly wrap the blank, such as shown in Figure 2, in a spiral-like manner. This is conveniently accomplished by engaging" the wide end a of the blank as shown in Figure 2 with a suitable clamp e on a mandrel e of a winding machine such as shown at e in'Figure 7, whereupon the blank is coiled in a manner suggested in Figure 3. During the winding or coilingof the strip, back tension is applied to the trailing end thereof by any suitable means. In the embodiment illustrated, a spring tensioning means at f acts in the direction of the arrows, which is contrary to the tension imposed on the blank by the winding operation. Usually the mandrel e will be of a collapsible type and the mandrel gear a .will be powered by any known type of driving mechanism.

Upon completion of the winding or coiling opblank, care will be taken that the square edge portion h of successive convolutions is maintained in alignment so that the end surface of the structure-resulting from the winding will be substantially perpendicular to the longitudinal -axis of the mandrel and, therefore. Perpendicular to the longitudinal axis of the laminated structure formed by the coiling operation.

Upon completion of the coiling operation the mandrel may be collapsed and the laminated coiled body produced will be removed therefrom.

' The next step is to assemble on the perpendicular end of the fabricated body a piercing head 1 which has previously been formed of cast or wrought metal. This piercing head will have a contour to give'it good penetrating and piercing" in some cases a plurality of spot welds will be made, as indicated. at 1'. .Alternatively, seam welds or riveted joints may be made along the approximately helical line where the rear edge s of an upper convolution intersects the surface of the next adjacent lower convolution; that is, along the line 3 of Figure 5. Such seam welds are shown at 10" in Figure 14, and a riveted joint is'shown at w in the same figure.

The bomb resulting from the practice of the novel method, it is clear, will have a laminated b d composed of a plurality of overlapping conlvolutions, and because of the tapering form of g cross'section of metal adjacent the piercing head where the greatest strength is required and the section will vary toward the tail, where a lesser wall thickness is satisfactory. This construction. such as shown in Figure 4, has the advantage over prior constructions in that it results in a more forward position of the center of gravity of the shell weight and a minimum shell weight for a given size and type of shell. The wall thickness may thus be made to exactly suit strength requirements. Moreover, the laminated body is advantageous from a standpoint of economy as it enables the production of a shell from readily produceable sheet or strip materiaL. Also the use of longitudinal seams, which are objectionable, is avoided. Only one continuous encircling helical seam is present and that is true because of the peculiar method of constructing the shell body. The seam follows a line which progresses at a constant rate from head to tail of the bomb. Therefore, any forces tending to rupture the seam are distributed over a great length ofseaimhence no one seam portion becomes overstressed. While I have specifically described the method of producing a tapered or streamline type of bomb by the utilization of a blank having converging edges such as shown in Figure 2, it is to be understood that in somecases a shell. with a laminated cylindrical wall may be mademerely by coiling a long flat strip with parallel sides, such as shown in Figure 15. I In the bomb body illustrated in Figure 4, the interior .andexterior surfaces of the various convolutions conform substantially to surfaces of cylinders having been wound on a substantially cylindrical mandrel.

In some cases, as illustrated in Figure 16,1

. contemplate winding the strip on a tapered man.-

Any conventional explosive such as shown byhatching a: in Figure 4 may be loaded within the interior of the shell body. I have illustrated somewhat. conventionally a tailbody closure n enclosing a suitable fuse '0 which is adaptedto beflred by a conventional form of air operated spinner 'p which is effective by a screw action after the bomb' has traversed"aipredetermined distance to actuate the fuse As, shown in Figurea 5 and 10, a plurality of fins q will be welded as at w in Figure 10 or bolted as at w to the laminated coiled body of the bomb, these fins being of conventional form and serving the usual function.

After assembly of the drel e'so that the surfaces of the convolutions will correspond to surfaces of a long tapering cone. when making such a tapered or cone-like laminated body, I 'will use 'a slightly modified form of blank such as illustrated in Figure 6. The .end of the blank will be cut-off at a suitable anglesas indicated atd and the-blank will be plotted by the use of certainv elemental lines (2' would be formed by severing. the strip'of Fig'u re laminated coiled body, 1 along the oppositely inclined lines a and b at and the edges d and (1 will follow properly.

the right of the figure. The laminated body so produced would in longitudinal section taper both voluted laminated tapering body 28 such as shown in Figure 11 might be aligned end to end with and secured intimately to a convoluted laminated body 13 having a substantially cylindrical exterior. Such a unit with a substantially cylindrical exterior is securable by winding a blank such as illustrated in Figure 2 by starting the winding operation from the pointed end; that is, from the reverse end to that illustrated in Figure 3. In this connection it is noted that when the winding operation is performed, as suggested in Figure 3, the interior chamber of the bomb body corresponds to a substantially true cylindrical surface, while the exterior is of a tapered or streamline form, as is clearly shown by the sectioned upper portion of the laminated body in Figure 4. When starting the winding operation from the pointed end of the blank of .Figure 2, the resulting convoluted laminated body will have a substantially cylindrical exterior and a tapering interior. Thus it will be appreciated that by joining the difl'erently wound convoluted bodies 13 and B" nested axially, as

shown in Figure 12, suitable variations as to overall interior or exterior longitudinal sectional contour of the bomb as a whole is attainable.

While I have described quite specifically the method followed in producing the type of bomb or shell illustrated, it is not to be construed that I am limited thereto and the description matter and drawings are to be interpreted in an illustrative rather than a limiting sense.

I claim:

1. In the manufacture of bombs, the method which comprises coiling an elongated metal strip so as to form a laminated hollow body, fastening certain convolutions to one another as the coiling proceeds so as to negative their tendency to uncoil, and securing a piercing head to one end oi said body.

2. In the manufacture of bombs, the method which comprises providing an elongated strip of sheet metal, tapering in width from one end 55 toward the other, coiling said strip into the form oi a laminated hollow body, securing to one another certain of the laminations thus produced as the coiling proceeds, and applying a piercing head'to one end of said body.

3. In'the'manuiacture of bombs, the method which comprises coiling an elongated metal strip while applying a back tension thereto so as to insure tight engagement between adjacent, convolutions oi' the laminated body thus produced, and securing a piercing head to one end of the laminated hollow body thus formed.

4. In the manufacture of bombs, the method I which comprises coiling an elongated metal strip while applying a back tension thereto so as to insure tight engagement between adjacent. convolutions of the laminated body thus produced, spot welding certain of the convolutions to one and securing a piercing head to one end oi the laminated hollow body thus formed.

5. In the manufacture of bombs, the method which comprises providing an elongated strip of sheet metal having parallel edges throughout the major portion of its length and tapered in width for the remaining portion or its length, coiling said strip into the form of a laminated hollow body, maintaining the laminations in coiled juxtaposition, permanently fastening adjacent laminations toone another, and assembling a piercing head therewith.

6. In the manufacture of bombs. the method which comprises providing an elongated strip or 15 sheet metal tapered in width from one end toward the other, coiling said strip into the form of a laminated hollow body, sequentially welding the laminations in coiled juxtaposition, assembling a piercing head therewith, and

homogeneously uniting the metal of the piercing head with that of one end of said body.

7. In the manufacture of bombs, the method which comprises providing an elongated metal strip whose forward end is relatively wide and which-tapers toward its rear end, coiling said strip about a collapsible mandrel, restraining the laminated body thus formed so as to prevent its inherent tendency to expand, collapsing the mandrel and removing the laminated body therefrom, and securing a piercing head to one end thereof.

8. A bomb of the character described having a piercing head united to a hollow laminated metal body comprising a plurality of convolutions attached to one another along the helical zone where they overlap.

9. A bomb of the character described including a hollow body portion comprising a continuous metal'strip convoluted into a succession d0 of overlapping laminations, a helical seam of weld metal-for preventing separation of such laminations, a piercing head secured to one end of said, body, and a fuse, containing structure secured to the opposite end thereof.

10. In the manufacture of bombs, the method which comprises coiling an elongated metal strip so as to form a laminated, hollow body, sequentially securing certain convolutions to one another so as to negative their tendency to. un- 5 coil, securing a piercing head to one end oi. said body and securing artail body to the other end. 11. In the manuiactureoi' bombs, the method which comprises coiling an elongatedmetal strip so as to form a laminated hollow body, sequentially securing certain convolutions to one another so as to negative their tendency to uncoil, welding a piercing head toone end of'said body and securing fins to the other end. 12. In the manufacture of bombs, the method 0 which comprises providing an elongated stripof sheet metal of substantially triangular ,form, coiling said strip so as to form a laminated hollow body, attaching certain convolutions thereof to one another by means of a helical seam weld so as to negative their tendencyto uncoil, and securing a piercing head to said body.

13. A body portion of a bomb of the character described formed of a plurality of units aligned axially and secured to one another, eachbody 10 unit comprising a continuous metal strip convoluted into a succession of overlapping laminations, and a helical seam of weld metal preventing separation of such laminations.

14. A bomb of the character described'having another so as toprevent the uncoiling thereof, '18 a piercing head united to a laminated hollow body, said body comprising a continuous convoluted metal strip with overlapping portions, the union of said head to said body providing the means for holding said laminations in close overlapped relation.

16.' In the manufacture of bombs, the method which comprises providing an elongated strip of sheet metal having parallel dges throughout the major portion of its length and tapered in width for the remaining portion of its length, 10

having one end edge substantially perpendicular to a side edge, coiling said strip into the form of a laminated hollowbody, maintaining the secured to said body.

HERBERT V. THADEN. 

